Monitoring treatment compliance and drug use is an important aspect of drug-abuse treatment programs and clinical trials for new treatment regimens. Urine drug testing is frequently used for these purposes. Hair may serve as a reservoir for drugs and other substances and may provide a more sensitive and broader window of detection for drug exposure. The presence of certain drugs and their metabolites has been demonstrated in human hair at times when plasma and urine drug concentrations are not measurable. Therefore, it may be possible to reconstruct a history of an individual's drug exposure via analysis of individual hair segments. The goal of this project is to acquire knowledge regarding the suitability of quantitative analysis of human hair segments for treatment drug compliance and use of abused-drugs in clinical trials of drug treatment regimens. Particular emphasis will be placed on the identification and use of a specific marker substance to establish time reference points in hair. To achieve these objectives the following specific aims are proposed. l) To develop ultra-sensitive and specific methods for the qualitative and quantitative measurement of treatment and potential marker substances in human hair. Specifically, we will develop sensitive and specific procedures using GC/MS for the detection and quantitation of treatment drugs such as buprenorphine and l-alpha-acetylmethadol and their metabolites in human hair. We will also develop sensitive and specific procedures using UV spectrophotometry and GC/MS for the detection and quantitation of a potential marker substance, phenazopyridine, in human hair. 2) To perform basic pharmacokinetic studies of the disposition of treatment drugs and potential marker substances in hair using in vitro techniques and in human subjects. First, we will determine if viable hair bulbs, held in vitro, can be used as a model to evaluate the incorporation of a marker substance such as phenazopyridine into hair in the presence of an abused drug (morphine) and a treatment drug (buprenorphine). Then, we will determine if the marker substance can be given to human subjects at specified, known intervals in order to establish reference points in hair between which drug use can be quantitatively measured. 3) To determine if quantitative analysis of hair segments can be used to evaluate drug-abuse and treatment compliance in a clinical study. Specifically, we will determine if the administration of a marker substance such as phenazopyridine can be used to establish reference points in human hair between which drug use and treatment compliance can be measured in subjects enrolled in clinical drug trials or drug treatment programs. Preliminary data presented demonstrate that we are able to perform all aspects of this proposal and that we will clearly be able to progress from analytical methods development, to in vitro studies of treatment drug and marker substance incorporation, to human studies with marker substances and treatment drugs.